1. Technical Field
The present disclosure relates to orientation detection circuits and, more particularly, to an orientation detection circuit capable of detecting four placement orientations of devices utilizing the circuit.
2. Description of Related Art
FIG. 7 shows an orientation detection circuit 10. The circuit 10 includes a vibration switch K1, a processor U1, a first resistor R1, and a second resistor R2. The vibration switch K1 includes a first terminal 11, a second terminal 12, a third terminal 13, a fourth terminal 14, and a metal ball 15. The processor U1 includes a first input pin IO1 and a second input pin IO2.
The terminal 11 is connected to the pin IO1 and connected via the resistor R1 to a power source. The terminal 12 is connected to the pin IO2 and connected via the resistor R2 to the power source. The terminals 13 and 14 are grounded. When the ball 15 contacts two of the four terminals 11, 12, 13, and 14, the processor U1 can obtain input states of “11”, “10”, and “01”, which corresponds to three different orientations of the switch K1. In other words, the circuit 10 can be used to detect three placement orientations of a device that utilizes the circuit 10.
However, in some circumstances, devices can be placed in any of four orientations and it may be desirable to be able to detect the four orientations.